How many chromosomes in a male sperm cell

What are two reasons for why a species might disappear from the fossil record?

Ais a landform that is formed at the mouth of a river from the deposition of sediment carried by the river as the water flows.

Suppose you use three different scale to weigh a bag of organges. one scale says the nag weighs 2.1 lb, and third says it weighs 2.1 lb. the actual weight of the bag of organges is 2.153 lb. which of the following best decribes these results?